EP2861421B1 - Vitrous roof endowed with lighting devices - Google Patents

Description

The invention relates to vehicle roofs made up at least in part of glazing. More specifically, the invention relates to roofs the glazing of which covers a large part of their surface, or even all of it.

Glass roofs are increasingly replacing traditional roofs which are part of the bodywork of vehicles. The choice of these roofs is the fact of the manufacturers to offer their customers this option giving the impression of the opening of the vehicle towards the outside, in the manner of a convertible, without having the disadvantages of the latter, the roofs maintaining the comfort of a traditional sedan. For this, glass roofs must meet many requirements. First of all, it is necessary to meet the safety obligations. Glass roofs must meet regulations that impose resistance to foreclosure in the event of an accident. In this sense they must comply with the rules designated "R43". Resistance to the eviction of passengers requires in particular the use of laminated glazing.

The presence of laminated glazing does not exclude the need to limit the weight. For this reason, the laminated roofs used must also have well-controlled thicknesses. In practice, the glazing of these roofs has a thickness which is not greater than 8mm and preferably not greater than 7.5mm.

The choice of glass roofs, as specified above, is intended to gain light in the passenger compartment. This gain must not be contrary to other properties which ensure passenger comfort, in particular thermal comfort. The presence of glass roofs, motivated by the increase in light, also leads to an increase in heat transfers with the exterior. This is noticeable in the greenhouse effect mechanism when the vehicle is exposed to intense solar radiation. But the roof must also help maintain the temperature of the passenger compartment in cold weather.

The control of thermal conditions leads to various measures including the use of high selectivity glazing. These conditions result from the choice of glasses used (most often mineral, but which can also be organic). They are also the result of the additional filters that these glazing include, in particular those formed by systems of layers selectively reflecting the infrared. The prior art reports solutions meeting these requirements. This is the case in particular with the patent EP1200256 .

The choice of glass roofs has also made it possible to develop additional functionalities, for example the integration of photovoltaic systems which contribute to the electricity production necessary for the operation of the various components of the vehicles. The implementation of such systems is the subject of numerous publications, and in particular of the patent EP1171294 .

Furthermore, the desire for increased brightness in the passenger compartment is not necessarily permanent. The user may, depending on the time of use, prefer less light, or simply maintain the “private” character which isolates the passenger compartment from external view.

To modify the light transmission of the glazing according to the conditions of use, solutions have been proposed previously. These are in particular so-called “electro-controlled” glazing, such as glazing comprising electro-chromatic means in which the variation is obtained by modifying the state of colored ions in compositions included in these glazing. It is also about glazing comprising layers of particles in suspension, which depending on the application of an electrical voltage are ordered or not, such as the so-called SPD systems (for “suspended particles devices”).

The development of glass roofs raises other questions and paves the way for new achievements. Certain functions can, or must be modified, taking into account the specificities of these roofs.

Among these functions is the lighting of the passenger compartment, whether it is ambient lighting or more localized lighting corresponding to what is termed “reading lights”. Traditionally, the means used for this lighting are arranged on the roof or on the interior lining thereof. Frequently also the lighting means form part of an assembly which extends in part over the windshield and which comprises the base of the interior mirror, various sensors controlling the triggering of the windshield wipers, that of the exterior headlights, together. which is also the support for means of data communication by means of waves of various frequencies (electronic tolls, GPS ...), or that of driving assistance such as infrared cameras. The assemblies in question are a local obstacle to the desired transparency which motivates the choice of these “glass” solutions.

The invention proposes to make the best use of the glazing constituting the roofs by integrating therein the means of lighting the passenger compartment so that the latter do not significantly alter their transparency. This integration, as described later, makes it possible to benefit from new arrangements adapted to these glazed roofs.

The mode chosen according to the invention is the use of light-emitting diodes (LEDs). This choice has been proposed previously, for example in the applications WO2004 / 062908 , EP1437215 , EP1979160 . According to these requests, the diodes are included in the plastic interlayer of the laminated glazing which combines the two sheets of glass. Depending on the demand considered, the LEDs are powered either by fine conductor wires ( EP1979160 ) or by transparent conductive layers ( EP1437215 ).

Beyond the principle of using LEDs for lighting, the prior art leaves open questions concerning the conditions which make these products meet the demands of manufacturers, and are effectively achievable in structural integration techniques. puffs considered. The inventors therefore propose solutions to these questions.

A requirement linked to the mode of use concerned is to have sufficient power, in particular for the constitution of reading light type.

Uses for the display of information in luminous form have been envisaged previously. The information display requires only a relatively low power, even when the display is located on a window exposed to light outside the vehicle, in other words against the light. The LEDs concentrate their emission on a very small surface so that the contrast with an external light remains sufficient even for a limited power. The same is not true for the “lighting” application. In a way, punctual power can even be a disadvantage. When the gaze is directly on these very intense point sources, there is a risk of dazzling the greater the greater the power delivered.

The light transmission of glass roofs is systematically limited, on the one hand to keep a character qualified as "private", and on the other hand to limit the energy input which is inseparable from the wavelengths of the visible range. For these two reasons at least the light transmission of glazed roofs is normally less than 50% and often much lower, for example of the order of 15 to 20% or less of the incident light. The transmission in question can be adjusted in various ways as indicated below, in particular by the use of sheets which absorb part of the incident light, but also by means which make it possible to control variations in transmission.

In determining the light power for a given lighting, it is necessary to take into account the elements which reduce the light emitted by the diodes, and in particular the fact that a greater or lesser part, depending on the glazing considered, is absorbed when passing through the sheets of glass, spacers and any element arranged in the path followed by the emitted luminous flux.

The light power necessary for the lighting according to the invention is advantageously distributed over a plurality of diodes. The multiplicity of diodes has several advantages. A first advantage is, for example, to only require the use of diodes of lower individual power. Even if the power of commercially available diodes has increased considerably, those of moderate power remain advantageous, if only because they remain less expensive. They are also advantageous insofar as the luminous efficiency of the most powerful diodes is not the best. It is therefore preferable to choose diodes which remain in the power ranges corresponding to the best efficiency. This way of doing things also responds to the need, which is discussed below, of limiting the negative consequences which are attached to the thermal conditions of use of the diodes.

The energy efficiency of diodes has also improved significantly over time. For a given power, the heat released tends to decrease in recent products. It remains that the best energy yields - that is to say the share of electrical power converted into light - do not generally exceed 30%, and most commonly remain in the order of 15 to 20%. The release of heat by the Joule effect is therefore significant.

The position of the diodes in the laminate does not facilitate the removal of the operating heat. For high power, the operation of a diode can lead to local heating such that it ultimately leads to deterioration of the diode itself, welds to the power supply circuit, or elements present in the laminated roof on contact. or in the immediate vicinity of the diode. While glass sheets can withstand a rise in temperature without damage, other constituents, including the thermoplastic sheets which assemble the laminate, require the temperature to be kept within relatively strict limits, most often below 100 ° C and even often below 80 ° C. For this reason, it is preferable according to the invention to distribute the total power required over several diodes, each offering only a fraction of this total power, these diodes remaining distant from each other.

The experiment makes it possible to determine the evolution of the temperature of a given power diode in an environment such as that corresponding to a laminated glass roof. This determination takes into account that the heat dissipation for a diode takes place essentially by conduction by the materials in contact with which the diode is in contact. PVB type thermoplastic interlayer materials are not good conductors, mineral or organic glass sheets are not either. Care must therefore be taken to contain the power of the diodes used. Experience shows that under the envisaged conditions of implementation and energy efficiency of the available diodes, the electric power should preferably not exceed 2w, and most often should not exceed 1w or even 0.5w. In the perspective of the evolution towards better energy efficiency, in other words for a lesser part of the power dissipated in thermal form, the power could be increased without risk. The continuation of this evolution can lead to the use of diodes of up to 4 or even 5w.

At a given electric power, the luminous flux of the diodes can vary to a large extent. In order not to have to unnecessarily multiply the number of diodes required, and to complicate their integration into the laminate, the power of the diodes used is not less than 15lm / w and preferably not less than 40lm / w and particularly preferably not less than 75lm / w. Conversely, it is preferable not to excessively increase their power so as not to risk heating which is detrimental to their longevity and / or the deterioration of the constituents of the laminate. The individual power of the diodes advantageously remains less than 100 lumens per electric watt.

The required light output may vary significantly depending on the vehicle and the use concerned (reading light, mood or welcome lighting).

As an indication, for a reading light, the required lighting is of the order of 20 to 100 lux, i.e. a luminous flux on the illuminated object, depending on the configuration of the vehicle interior, which is not less than 1lm , preferably not less than 2lm and may amount to 50lm or more. For interior ambient lighting the light output is normally a little less. Illumination ordinarily is not less than 1lux and may be 10 lux or more. Under these conditions, the luminous flux for ambient lighting for the entire passenger compartment can range from 2 to 60 lumens.

Another factor influencing the lighting, is related to the orientation of the luminous flux. For the most common diodes, the emission takes place in the entire space facing the diode. For this, the diode has a reflector element which directs the flow on one side only. Note that if diodes can be provided with optical means which concentrate and direct the emitted luminous flux, these means are inoperative when they are included in a medium of neighboring refractive index. These optics made up of synthetic materials of the epoxy resin type do not exhibit a sufficient index difference with the thermoplastic materials of the interleaves of the laminate, such as polyvinyl-butyral. Consequently, mastering the directivity of the beam advantageously involves the use of additional means. Examples of implementation modalities are presented below.

In practice, for reading applications, the power of the diodes is chosen taking into account the absorption of the constituents of the glazing, so that the light intensity emitted outside the glazing in a solid angle of 40 ° normal to the glazing by each diode is not less than 10cd and preferably not less than 15cd.

Taking into account the luminous flux emitted by the most suitable diodes available, a reading light advantageously comprises from 2 to 20 diodes and preferably from 6 to 15. For diodes which would be more powerful, only one of them could be suitable, for as long as its efficiency is high enough. For general lighting of the passenger compartment, the number of diodes depends on the dimensions of this passenger compartment, it may be much greater than the previous one. Relative to the surface of the roof, the number of diodes distributed on this roof can advantageously be of the order of 6 to 40 / m ² , and most often 10 to 30 / m ² .

Whether it is reading lights or mood lighting, it is preferable to keep the diodes at a certain distance from each other to facilitate the thermal dispersion of which they are the seat. A spacing of at least 10mm between each diode is preferred, and advantageously at least 20mm.

As pointed out above, the light transmission of glass roofs is necessarily limited. This absorption is traditionally obtained by the glass sheets and spacers used. This absorption can also come from absorbent layers present on the sheets or from the use of devices making it possible to control various states of transmission, or even from the combination of several of these means.

When the absorption is obtained by the glass sheets and the spacers, overall and / or individually these elements are very absorbent. However, a strong absorption of this type can also be advantageous in the composition of roofs comprising transmission control elements, to further reduce the light and energy transmission and / or for example to control the coloring of the glazing.

In roofs which include means for varying the transmission in a controlled manner, means which are discussed below, the absorption by the glass sheets, possibly that of the spacers, may be less. Electro-controlled systems in their "clear" configuration contribute to an absorption that usually does not exceed 50%. If the desired transmission in this state of the electro-controlled system is considered insufficient, the glass sheets and spacers must participate significantly in the reduction of the transmission. This absorption in this case can still be very important. It is preferably at least 25% and may be 40% or more. The absorption in question occurs whether the device is in the light or dark state. In the clear state, it contributes to the reduction of light and energy transmission, and possibly participates in the masking of the elements contained in the glazing.

The glass sheets used to constitute the laminate can be of the same composition and optionally of the same thickness, which can make the prior shaping easier, the two sheets being for example curved simultaneously. Most often the sheets are of different composition and / or thickness and in this case, they are preferably shaped separately.

The choice of glass sheets is preferably such that both the transmitted light and the reflected light are as neutral in color as possible. Overall, the glazing has a gray or slightly bluish color.

The possible presence of colored inserts contributes to light absorption. The presence of these colored spacers does not significantly contribute to a decrease in energy transmission. Their use can be envisaged for glazing for which the sheets of glass on the whole are not sufficiently absorbent. This situation may be encountered, for example, when, in order to integrate photovoltaic elements into the glazing, at least the outer sheet of glass may be a sheet of glass that is not very absorbent, or even of extra-clear glass. Apart from this particular hypothesis, most often the outer sheet is a sheet of glass which is also absorbent, and recourse to a colored interlayer is not necessary.

The glass sheet facing the passenger compartment can also exceptionally be clear glass. It is most often absorbent and contributes to the reduction of the overall energy transmission. When its transmission is limited, it makes it possible to hide from the view of the passengers, at least in part, the non-transparent elements present in the glazing. This is the case, for example, with the diodes themselves when they are not activated, but it can also be the photovoltaic elements referred to above, or any element incorporated in the glazing.

Preferably, the two glass sheets are colored and the light emitted by the diodes is partly absorbed by the glass sheet facing the passenger compartment, and by the insert in which the diodes are inserted. Not to not excessively reduce the light emitted by the diodes, the glass sheet facing the passenger compartment preferably does not absorb more than 40% of this light and preferably not more than 30%.

In the choice of glass sheets and spacers also intervenes the color in transmission and reflection. For the glass sheet facing the passenger compartment, a glass which is particularly neutral in transmission is desirable because of its effect on the coloration of the light flux coming from the diodes.

For the constitution of a reading light, the light is preferably white or very slightly tinted. The colorimetric coordinates (x, y) in the CIE 1931 system, characterizing the lighting, taking into account on the one hand the emission of the diodes but also on the other hand the transmission by spacers and the glass sheet facing towards the passenger compartment, are such that they fit advantageously within a perimeter defined by the coordinate points: (0.2600; 0.3450), (0.4000; 0.4000), (0.4500; 0, 4000), (0.3150; 0.2900), (0.2350; 0.2500), perimeter including both so-called cold lights and hot lights, and preferably in the perimeter defined by the coordinate points ( 0.2650; 0.3350), (0.3200; 0.3200), (0.3100; 0.3000), (0.2350; 0.2500) which more specifically targets very weakly colored lights.

As indicated above, efforts are made to limit the energy transmission of glazed roofs exposed to solar radiation by the choice of glasses which compose it, and also, where appropriate, by the use of thin layers selectively reflecting infrared. For passengers, the presence of glass roofs can also lead to what is termed a “cold shoulder” sensation, a sensation caused by heat loss from the passenger compartment when the outside temperature is lower than ambient temperatures for comfort.

In practice, to restore passenger comfort, manufacturers essentially use an awning which makes it possible to cover the glazing from the inside over its entire surface. But the presence of a canopy, when it is extended, does not allow to benefit from the lighting incorporated in the roof.

To avoid the use of the awning, the invention proposes roofs for which heat loss is minimized, and this without excessive reduction in light transmission. To achieve this result, the invention proposes the application of low-e layers (low-emissive layer) on the face of the glazing facing the passenger compartment. In the traditional designation of the faces of laminated glazing, this is position 4. The numbering of the faces is done starting from the face exposed to the external atmosphere. The layers in question act as a filter selectively reflecting the infrared rays emitted from the passenger compartment, without constituting a significant obstacle to the transmission of the rays of the visible range from the outside to the inside.

The presence of these layers offers the advantage of keeping the lighting functions according to the invention available in all circumstances.

The presence of thin layers in position 4 is chosen despite the fact that in this position the layers are not protected against damage, in particular mechanical damage. It is possible to choose low-e layers which offer sufficient mechanical and chemical resistance.

The infrared filter function can be more or less “selective”. Selectivity is defined as the ratio of visible transmission (TL) to solar factor (FS), the latter being the sum of the energy transmitted directly and that absorbed then re-emitted inside, according to the definitions of the EN standard. 410.

Advantageously, taking into account the importance of having coatings of good mechanical strength, so-called “hard” layers are chosen, such as those produced by techniques of the pyrolytic, CVD or PECVD type. But low-e systems can also be prepared by vacuum sputtering techniques, provided that these systems are composed of sufficiently strong layers.

According to the invention, it is preferred to use a system of low-emissive layers, the emissivity of which is less than 0.3 and preferably less than 0.2, and particularly preferably less than 0.1.

In the preparation of the roofs according to the invention in general, it is necessary to consider the capacities of the constituent elements to withstand the treatments which lead to the shaping and the assembly of the glazing. Starting from the basic elements: glass sheets, spacers, diode supply circuit, the diodes themselves, low-emissive layers, the treatments necessarily include the formation of the layers, the bending of the sheets, finally the assembly of the various elements.

The roofs of vehicles generally have relatively slight curvatures with the possible exception of those of the edges of these glazing. The shaping of sheets of mineral glass comprises, at least for one of them, a treatment which requires a passage at high temperature (650-700 ° C) leading to softening of the glass. The temperatures in question are not bearable by the diodes and certain elements associated with them. The diodes must therefore necessarily be introduced into the glazing after bending. Their integration remains subject to the assembly of the glass sheets with the thermoplastic interlayer sheets.

The conditions for introducing the diodes must take account of their relative fragility both at high temperatures and at mechanical stresses. The assembly of the sheets is usually obtained in an oven at a temperature of the order of 120-130 ° C., and under pressure.

The nature of the diodes normally makes it possible to withstand the temperatures in question as long as they are not imposed over very long periods and / or under aggressive chemical environmental conditions. The temperature in question nevertheless requires some precautions with regard to the choice of materials ensuring the connection between the diodes and their supply circuit. This connection is sensitive to heat especially when carried out using conductive glues. If necessary, the use of welds can withstand higher temperatures.

The mechanical stresses are mainly linked to the pressures resulting from the assembly. To minimize the effect of these pressures, it is necessary to arrange the diodes so that they fit into the material of the spacers without excessive effort.

A first condition is to ensure that the thickness of the interlayer is sufficient for the insertion of the diodes.

The usual diodes with their envelope (“packaging”) usually have heights of less than 1.5 mm and most often of less than 1 mm, or even less than 0.7 mm. The heights in question are perfectly compatible with the thickness of the traditional dividers used. As an indication, PVB sheets are commercially available in thicknesses of 0.76mm and 0.38mm. In addition, it is conventional in these laminated glazing to combine several intermediate sheets as required. According to the invention, the thickness of the spacers is therefore at least equal to the height of the diodes. As an additional precaution, the thickness of the interlayer intended to surround the diodes is chosen to be greater than the height of the diodes, for example 1.5 times this height or more without exceeding what is necessary so as not to unnecessarily increase the total thickness of the glazing. .

The mechanical strength of the diodes, and even more so of their connection to the power supply circuit, must allow their insertion into the material of the spacers during assembly. The ordinary ceramic packaging is very resistant. The softening of the intermediate material when passing through the oven is usually sufficient to allow the insertion of the diodes by simple pressure.

The implementation described above can be replaced by the less usual one in which the interlayer would be made from a material applied in fluid form at room temperature, before proceeding with its hardening, for example by crosslinking, once the various elements are in place.

The diode supply circuit can be formed in different ways. One of them consists in having thin wires which are advantageously introduced into the insert with the diodes as described in EP1979160 . The presence of very fine wires is hardly noticeable insofar as the glazing systematically exhibits reduced light transmission. The main difficulty for this embodiment consists in placing the diodes in the interlayer.

According to the invention, the power supply circuit and the diodes are arranged on a support separate from the intermediate materials.

Taking into account the difficulty of handling relatively thin sheets of large dimensions on which the diodes are fixed beforehand, it is possible to proceed in a different manner. This involves introducing into the laminate an element independent of the glass sheets and the spacers themselves. The circuit and the diodes are arranged on a thin support element which is inserted into the laminate. The dimensions of this support element can be relatively small compared to the surface of the roof. They will advantageously be limited to what is necessary for the appropriate arrangement of the diodes. For an e-reader, for example, the support may be limited to an area of the order of a few square decimetres or less.

The support element of the circuit and of the diodes consists of a thin glass plate. Given the dimensions, which may be limited, the blade may be of particularly small thickness, for example of the order of 0.1 mm. Such thin sheets have the advantage of being easily deformable to adapt to the curvatures of the laminated roof. To improve the flexural strength, these sheets are, as previously, advantageously chemically tempered. In addition the Glass elements can withstand temperatures consistent with soldering the diodes to the circuit.

The insertion of the diode support is preferably facilitated by the establishment of a housing provided in the intermediate sheet or sheets. This mode is traditionally proposed for the insertion of various elements, in particular photovoltaic cells in laminated glazing, including in roofs as in EP1171294 . It is also a mode proposed in WO 2005/102688 for SPD type assemblies intended to vary the light transmission.

The composition of the supply circuits must meet several requirements. First, if, as is preferred in order to best preserve the uniformity of transparency, a support for the diodes which is transparent is used, the power supply circuit will itself preferably be such that it does not appreciably modify the light transmission, or , more precisely that its presence remains practically undetectable visually. In this case, the circuit is for example made of an essentially transparent conductive coating. But very fine threads can also be used.

For transparent circuits, thin conductive layers of the so-called “TCO” (thin conductive oxide) type are advantageously used, or systems comprising at least one metal layer. These conductive layers come in very thin thicknesses and are used in many fields, including in particular that of photovoltaic cells. For oxide layers, the conductivity is lower than with metal layers, which Usually leads to significantly greater thicknesses. In all cases, even for thicknesses of several tens of nanometers, the limited impact on the light transmission is not a problem given that the very low overall transmission of the glazing itself.

The choice of conductive layers must also take into account their electrical characteristics. The layers of conductive oxides usually have relatively low conductivities, in other words non-negligible resistances. The layers of conductive oxides have for example a resistance of the order of 10Ω / □ or more. The systems comprising metallic layers have lower resistances, of the order of 1 to 5Ω / □, but exhibit a certain fragility which means that, despite their qualities, the layers of conductive oxides remain preferred.

In practice, it is important to maintain the resistivity of the layer at a sufficiently low level so as not to have an excessive Joule effect. As for the diodes, additional heating must be avoided, the greater the higher the resistance, even if the heat produced is distributed over the entire surface occupied by the conductive layer.

The electrical circuit supplying the diodes is formed on the conductive layer in a traditional manner. For a support consisting of a thin glass slide, a usual method consists, for example, in cutting the layer beforehand uniformly covering the support. This cutting is advantageously carried out by ablation by means of a laser. For supports consisting of thin films such as those of PET, the circuit is preferably formed by printing techniques.

In traditional packaging, the luminous flux emitted by the diodes is distributed over a beam with a wide aperture, which can reach 180 °, and is at least 120 ° depending on the envelope used. Ambient or welcome lighting accommodates this particularity well when it is combined with a regular distribution of diodes over the entire roof.

If the light beam is wide open, its intensity is not uniform in all directions. It is strongest in the direction normal to the plane of the semiconductor of the diode, and decreases to its widest opening. This distribution is detailed later with regard to an example and the figure which relates to it.

Even if the intensity is greatest in a direction which can be chosen by the location of the diodes in the roof, this intrinsic partial "directivity" may not be sufficient. The formation of a flow directed so as to obtain a beam of reduced angular aperture may be preferred.

In order to reduce the aperture of the light beam coming from one or more diodes, it is advantageous to constitute a converging optic opposite them. If this optic is original on the diode, so that it remains effective in the laminate, its refractive index must differ from that of the intermediate material in which it is inserted. The most widely used products have an epoxy resin optic, the refractive index of which does not differ appreciably from that of the usual intermediate materials. In this situation to obtain the required convergence, the optic is placed not on the diode but on the face of the glazing facing the passenger compartment, therefore in position 4. The optic in question in principle can be an integral part of the sheet. glass itself by modifying its surface. However, for reasons of economy of implementation, it is advantageous to have the optics in the form of an added part which is arranged opposite the diodes. The part in question is designed in a transparent material which can be glass, but also if necessary a sufficiently transparent and resistant polymer material.

To minimize the protrusion towards the passenger compartment, resulting from the presence of this attached optic, the Fresnel lens shape is preferred. With such an optic it is possible to choose the angle of opening of the beam which corresponds best with the dimension of the zone which one wishes to illuminate. For reading lights, an opening of 15 to 40 ° makes it possible to adjust the dimensions of the illuminated zone taking into account the distance separating the source from this reading zone.

For fixed directional lighting, the optic is placed on the internal face of the glass sheet facing the passenger compartment and glued to this face in a non-modifiable manner. It is also possible to envisage an orientable beam, the direction of which can be modified for example by translation of the optic on the face of the glass sheet. Such a means requires the presence of a device which necessarily adds to the protuberance on the surface of the sheet.

The light beam can be limited as indicated above by a kind of diaphragm associated for example with each diode. This way of proceeding, unlike the optical device, only makes it possible to recover a limited fraction of the flux emitted. It is also possible to combine the use of the diaphragm and of an optic as indicated above.

Having a glass roof on a vehicle aims at least in part for an aesthetic as well as a functional objective. For this reason it is preferable that all the means associated with these roofs contribute to the achievement of this objective. The presence of lighting means included in the roof must necessarily be accompanied by a specific power supply and controls for these means.

Powering the diodes requires a specific voltage. As indicated above, this voltage is of the order of a few volts (2 to 4v most often). It must necessarily include means for adjusting the voltage which supplies the other components of the vehicle, these depending on whether they are cars or large utilities of the order of 12 to 14v or of the order of 48v. The voltage conversion means, even miniaturized, cannot be included in the laminate of the glazing. In order to bring together all the elements participating in the function, or the necessary transformers can be placed near the glazing. Advantageously, the transformer is placed under the enamelled zone which masks the edges of the glazing.

Lighting control can include simple switches. In traditional lighting modes, switches are located in the immediate vicinity of the lighting means to avoid complex circuits and facilitate identification of the means operated. Traditional switches do not respond to the concern for transparency at the origin of the choice of glass roofs.

The invention proposes to use means for controlling the diodes which are also essentially transparent. To this end, the invention proposes to use switches, the implementation of which is triggered by means of relays actuated by a pulse linked to an electrical quantity. Preferably, the switch used is of the capacitive type. This mode is the one which allows the best use of the very structure of the elements included in the roof with the diodes.

As an indication, a capacitive sensor can be of the direct contact type. The sensitive element is for example a zone delimited in the low-e layer situated on the face facing the passenger compartment. The low-e layers being conductive can serve as a sensor for controlling the interrupt relay. The advantage of direct contact is that the change in capacitance induced by contact can be relatively large so that the threshold controlling the switch can be high enough to rule out any parasitic tripping.

The sensor can also be in indirect contact. In this case, the sensor is located inside the glazing. Advantageously, the sensor is incorporated in the conductive layer in which the supply circuit of the diodes is formed. This sensor is for example formed by a delimited zone independent of the diode supply circuit. The modification of capacitance is then induced indirectly by modification of the electric field by bringing the hand closer to the location of the electrode in the glazing. The fact that a glass sheet is interposed limits the modification induced and consequently requires that the detection threshold be lowered, possibly leading to an increased sensitivity to parasitic triggers.

In particular, when adjusting the sensitivity, it is advisable to ensure that the triggering threshold is greater than that which corresponds for example to the presence of water on the outer sheet of glass. A conductive layer grounded and interposed prevents parasitic effects. This conductive layer can itself be transparent.

In the embodiments of the conductive circuits supplying the diodes, it is preferred that the latter be little or not discernible in the roof. If a capacitive sensor is formed as indicated above in the conductive layer, the latter is not easily discernible either. The location of this "switch" by the user can be facilitated in a tactile manner. The presence of protruding optical means, in particular of the Fresnel lens type on the surface of the interior face of the roof is an example of this, but a simple frosting may suffice. It is also possible to locate the sensor optically by adding a very low intensity diode supplied permanently as soon as the vehicle's ignition is actuated, or again in a similar manner by maintaining the operation of the reading light but at a level. very low operation.

The embodiments of the invention proposed above relate to the combination of lighting means in roofs made up of sheets of glass which make it possible to set certain levels of light and energy transmission. The glazing according to the invention can comprise means which make it possible to vary these transmissions and especially the light transmission at will. Means for this purpose, as indicated above, are in particular electro-chromatic devices. These are also and preferably the SPD systems.

Roofs whose light transmission is modified by the implementation of SPD are particularly interesting because of their very fast response to the command. The variation in light transmission obtained with these SPDs between the two states "clear" and "dark" depends on the systems chosen. In conventional products of this type, the variation in transmission between these two states may reach 40% or more, with transmission in the dark state which may be extremely low. Moreover, the presence of these systems also leads to a very reduced energy transmission whatever the light or dark state in which they are. This reduction in energy transmission is linked in particular to the measures taken to avoid subjecting the functional elements, which are these orientable particles, to an excessively high rise in temperature. It is also linked to the fact that a significant part of the energy accompanies the wavelengths of the visible. Reducing transmission in the visible automatically leads to a reduction in energy transmission.

Since the SPD components are relatively fragile when exposed to heat, it is particularly important, since the diodes would be located in the immediate vicinity, that their operation does not produce an excessively high rise in temperature. The choice of the power and of the distribution of the diodes at a distance from one another, as indicated above, makes it possible to satisfy this condition.

When the diodes are located in the same perimeter as the SPD film, the diodes are located under this film, in other words more towards the passenger compartment, so that the emitted light is not absorbed for a significant part by the film than the one. - here either in the "dark" state or in the "light" state.

• la figure 1 représente schématiquement en perspective éclatée un ensemble partiel d'éléments entrant dans la constitution d'un toit selon l'invention ;
• la figure 2 est un schéma en coupe d'un support des diodes ;
• la figure 3 représente de manière schématique un circuit d'alimentation pour 8 diodes ;
• la figure 4 est un schéma illustrant une distribution de l'intensité lumineuse dans un faisceau émis à partir d'une diode ;
• la figure 5 représente un mode de contrôle du faisceau lumineux ;
• la figure 6 montre de manière schématique un mode de réalisation dans lequel le vitrage comporte un système de couches basses-émissives ;
• la figure présente en perspective éclatée, des éléments d'un vitrage comportant un ensemble SPD ;
• la figure 7a montre un détail du film SPD de la figure 7 ;
• la figure 7b montre de manière schématique des éléments de protection d'un ensemble SPD ;
• la figure 8 présente sur le diagramme de colorimétrie CIE 1931 les périmètres préférés des couleurs du faisceau lumineux d'éclairage selon l'invention.

The invention is described in detail with reference to the examples illustrated by the drawing boards in which:

• the figure 1 schematically shows in exploded perspective a partial set of elements entering into the constitution of a roof according to the invention;
• the figure 2 is a sectional diagram of a diode support;
• the figure 3 schematically shows a power supply circuit for 8 diodes;
• the figure 4 is a diagram illustrating a distribution of light intensity in a beam emitted from a diode;
• the figure 5 represents a method of controlling the light beam;
• the figure 6 schematically shows an embodiment in which the glazing comprises a system of low-emissive layers;
• the figure shows, in exploded perspective, elements of a glazing comprising an SPD assembly;
• the figure 7a shows a detail of the SPD movie of the figure 7 ;
• the figure 7b schematically shows the protection elements of an SPD assembly;
• the figure 8 presents on the CIE 1931 colorimetry diagram the preferred perimeters of the colors of the illuminating light beam according to the invention.

All the elements of the figure 1 is an exemplary embodiment according to the invention. The elements are presented as they are before they are assembled. In this figure the curvatures of the sheets are not reproduced for the sake of simplicity. In practice, roofs, glazed or not, have curvatures which are usually more accentuated on the edges at the location of the attachment to the bodywork for a docking chosen for its "design", aerodynamics and "flush" appearance. ”Corresponding to a good surface continuity between the contiguous elements.

In practice, glazing occupies an increasing part of the roofs, even covering in some cases almost all of these roofs. Where appropriate, given the dimensions, the roofs include several juxtaposed panels to cover as much of the surface as possible. In this case the different parts can be made up of glazing offering the same composition, in other words offering the same functionalities, they may also be dedicated to distinct functions. AT As an indication, it is possible to find on the same roof a part comprising photovoltaic cells, and therefore essentially opaque to light transmission, and another part which has the role of arranging a certain light transmission.

The glazing of the figure 1 comprises two sheets of glass, external 1 and internal 2. Most frequently these two sheets are of highly absorbent colored glass, so that the light transmission is limited for example to less than 50%, and in a configuration of this type preferably less than 30%. The two sheets may or may not be of the same composition, but their combined coloring is such that the color in transmission is neutral.

Glasses used for these sheets are for example gray glasses as described in the patent. FR2738238 or in the patent EP1680371 , or gray glasses with a green tint as described in EP 887320 , or in blue shade as in EP1140718 .

To the figure 1 , the glass sheets are presented without the enamelled patterns which traditionally are used to hide the edges of the glazing. Enamels of this type would, for example, be placed on the internal face of the sheet 1, therefore in position 2, concealing all of the bonds and connections located at the edge of the glazing. The masking enamels can also be in position 4, in other words on the face of the glazing exposed inside the passenger compartment. But in this position, for an observation from the outside of the vehicle, they do not mask the elements included in the laminate. It is also possible to arrange the masking in position 2 and in position 4.

In the example presented, the support for the diodes 6 consists of a clear glass plate 5 (for example 0.4 mm thick). The diodes 6 are soldered or glued to the power supply circuit formed in a layer of conductive oxide, not shown. The height of the diodes on the glass slide 5 is for example 0.6 mm.

Sheets of thermoplastic material 3 (thickness 0.38mm), 3 '(thickness 1.14mm) and 4 (thickness 0.38mm), of PVB type complete the set. Sheets 3, 3 'and 4 are also transparent. To facilitate the insertion of the blade 5 carrying the diodes, the sheet 4 is of a thickness close to that of the blade 5, and has a cutout corresponding to the dimensions of this blade.

On assembly, the intermediate sheets subjected to an oven and under vacuum, stick to each other and to the glass sheets. The maintained vacuum allows the evacuation of air bubbles that could be trapped.

In the assembly the interlayer material is sufficiently softened so that the diodes penetrate into the sheet 3 'without requiring excessive pressure. The position of the diodes fixed on the sheet 5 remains that which is theirs before this assembly.

The glass sheets 1 and 2 are respectively 2.1mm and 2.1mm thick. The assembled glazing has a total thickness of 6.1mm.

Sheet 1 is of green glass, the optical characteristics of which are under 4mm thick and an illuminant A:
TL A4 27.3%; TE414.8%; λ _D 486nm; P 18
(λ _D is the dominant wavelength and P is the excitation purity).
Sheet 2 is of gray glass, the characteristics of which are:
TL A4 17%; TE415%; λ _D 490nm; P 1.8

The assembled glazing has the following optical characteristics: TL A 19%; TE 12%; λ _D 493nm; P8; and a color rendering index of 78.

The figure 2 schematically shows in section the glass slide 5 on which is applied the conductive layer 7 cut so as to constitute the supply circuit of the diodes 6. The diodes are soldered to this layer. They are gathered over a limited area to lead to a concentrated beam of sufficient power. The conductor circuit is formed so as to separate the supply poles, each diode being soldered to each of the two poles.

A schematic circuit is for example presented in the figure 3 . The blade 5, seen from above, comprises a conductive layer which is applied to the major part of the blade. The layer is divided to constitute the supply circuit for the diodes shown at 6. The layer is in two symmetrical parts retaining a large surface area to dissipate as much as possible the heat produced in this layer by the Joule effect. The dimensions of the surfaces of these conductors are also determined so as to guarantee a practically identical supply current for each of the diodes. The arrangement of these, which is of the “parallel” type along these conductors, can lead to a difference in the current flowing through the different diodes. The configuration of the electrodes is chosen so as to minimize these differences and the power delivered. Each part supplies 4 diodes and is itself divided into two (17 and 18) each corresponding to a supply pole (+, -). The diodes 6 are each connected to the two poles.

To form the circuit, the layer 7 initially extends uniformly over the entire surface of the glass sheet 5, possibly with uncoated edges. The separation of the different zones in this layer is obtained along lines 21, traced in this layer for example by ablation by means of a laser by well known prior methods. The width of the ablation is limited to what is necessary to ensure that the areas are well electrically isolated from each other.

The distribution of the diodes is made so as to distribute the heat produced during operation as well as possible. The diodes are spaced from each other, but at a distance limited by the need to collect the resulting light emission. In the example, the diodes are arranged in a circle with a diameter of 6 cm.

By way of example, the conductive layer is an ITO (“indium tin oxide”) layer with a resistance of 10Ω / □. The ITO layer is interesting in particular because of its color neutrality. It does not significantly modify the aspect in particular transmission.

The figure 3 also has an electrode 19 cut from the conductive layer, like the diode supply circuit. This electrode is connected to an assembly controlling the switch of the diodes in a circuit of the capacity variation type. The charging time of the electrode is controlled by its capacitance itself varying as a function of the conductive elements placed nearby and which modify the electromagnetic field. The operator's movement in this direction thus triggers a diode switch relay. Where appropriate, the circuit in a known manner can also include a variator (“dimmer”) leading to different supply levels for lighting of varying intensity, each pulse passing from one level to another.

To limit parasitic tripping, the conductor 20 for connecting electrode 19 to the device, not shown, has as small a surface area as possible. Likewise, if the sensitivity of the electrode 19 is such that in particular the presence of water on the roof is detected as a lighting control, a conductive screen connected to ground is advantageously interposed between this electrode and the exterior of the roof. This screen can take the form of a thin conductive layer. This thin layer can for example cover the other face of the blade 5. Optionally the electrode 19 and the conductor 20 which connects it to the switch device can be surrounded by a conductive zone also cut in the layer and connected to the mass, to also reduce the possible incidence of neighboring electric fields.

The conditions set for a reading light are for example to have a given sufficient illumination on a surface and at a determined distance. In one example, the distance is 0.6m between the roof and the surface to be lit, which is fixed to a circle with a radius of 0.25m. The minimum illumination required on this surface is for example 55 lux.

In the example considered, the diodes used are of the Nichia brand of the NS2W150A type. These are medium power diodes producing a "cold white" light. They are supplied at a voltage of 3.2v and each at an intensity of 0.100A.

The light intensity given by the manufacturer is 17.4cd for an intensity of 0.150A. One can estimate on the field considered that the luminous intensity is approximately proportional to the electric intensity. This light intensity according to the normal to the diode is therefore established at approximately 11.6 cd. It varies according to the direction considered in the manner presented in the graph of the figure 4 . Thus without optical means modifying the direction of the luminous flux, for the angle of 23 ° on either side of the normal, which corresponds approximately to the illuminated zone sought for the conditions indicated above, the luminous intensity for a diode is about 10.45cd. It takes into account the incidence of the insertion of the diodes in the laminate, and in particular of the reflections and of the light absorption on the path of the beam. Finally, to achieve the necessary illumination, around 8 diodes of this type are needed to constitute the reading light.

The fact of using a plurality of diodes of limited power apart from the control of the local heating, also reduces the effect of glare which can come from a direct observation of the diodes. This effect can be further minimized by promoting a certain diffusion of the light beam, for example by frosting the internal sheet at the location corresponding to the diodes.

The luminous flux emitted by the diodes is characterized by colorimetric coordinates reported on the diagram of the figure 8 and represented by the limits designated globally by N. The field as presented by the manufacturer is subdivided into parts corresponding to distinct classes left to the choice of the user. The manufacturer proposes, if necessary, a preliminary sorting so that all the diodes are located in only one of these parts. This selection, which makes it possible to refine the color, comes at an additional cost. The same graph shows the perimeter P corresponding to the preferred color according to the invention. Note that this color which covers in large part that of the diodes, also takes into account the incidence of the glass sheet which is interposed between the diodes and the passenger compartment, and possibly of the interlayer if the latter is chosen in color.

In the previous example, the diodes emit a flow of slightly bluish white light which is qualified as “cold”. If a "warm" light is preferred, one can choose a product of the same type as that of Nichia referenced NS2L150A. The spectrum of these diodes corresponds to the perimeter designated by M.

As indicated above, more powerful diodes are possibly used, but apart from an additional cost, they have the disadvantage of a shorter life.

The arrangement of the 8 diodes in the laminate does not lead to harmful heating. For continuous operation in a still atmosphere at ambient temperature of 25 ° C, the glazing being arranged in a substantially horizontal position, the temperature rises to about 35 ° C. These temperatures do not affect the diodes or the components of the glazing.

Without means of concentration, the luminous flux emitted by the chosen diodes is distributed as shown in the graph of the figure 4 . This graph shows the scale of light intensities horizontally. The concentric semicircles show the intensity fractions from 0 to 100% of the strongest intensity that lies vertically. The intensity is read on the graph at the intersection of the line corresponding to the direction with the circle C. The light intensity decreases rapidly with an increasing angle with respect to the normal to the source. It is only about half for an angle of 60 °. This distribution can be satisfactory if, apart from the surface which one wishes to illuminate, it is not inconvenient to have a certain luminosity. In the opposite case, the light beam should be restricted.

The figure 5 schematically shows in section, one side of the roof glazing comprising a set of diodes 6, on a support 5 consisting of a glass slide. The assembly of diodes 6 and their support 5 is incorporated as above in a material formed from several plastic spacers (3, 4, 3 ').

The figure 5 illustrates the fact that the luminous flux emitted by the diodes 6 is distributed in a widely open beam. Without any other device than the reflector which is part of the envelope of the diode, the initial flux develops on an angle at the origin, in other words in the intermediate material and in the sheet 2, which can go up to 180 ° and is usually not less than 120 ° depending on the configuration of the diode envelope. This is represented by the angle α ₁ .

When you want to limit the beam, additional measures are necessary. The figure 5 schematically illustrates the use of Fresnel optics 8 on face 4 of the glazing facing the diodes. The beam is thus brought back to a more restricted angle α ₂ .

Another mode capable of producing a less widely open beam consists in the use of a diaphragm which limits the flow to the part directed in the desired direction. The diaphragm can be formed in an opaque enamel pattern 9, applied to the face of the glass sheet 2 facing the passenger compartment. This arrangement must be applied to each diode individually. It is therefore necessary for the respective positions of the diodes and of the openings in the opaque enamel layer to be rigorously established.

The graph of the figure 4 illustrates the effect of an example of this mode of limiting the beam per diaphragm. The diaphragm is shown schematically by the two arrows defining its opening. The enamel 9 is placed 3mm from the source, the dimension of which is that of a diode, ie approximately 2.5mm. The free enamel opening is 0.5mm. In this configuration, the beam opens at an angle of 48 °.

The figure 6 schematically illustrates the use of a low-emissive layer system 10, applied in position 4. In this position, the layers are not protected against mechanical or chemical alterations originating from the passenger compartment. This provision is nevertheless necessary for achieve the required efficiency. The oxide-based layers obtained by pyrolysis offer good mechanical resistance.

The most usual "low-e" (low-emissive) pyrolytic systems include a doped tin oxide layer deposited on a first layer whose role is to neutralize the color in reflection. The layer in contact with the glass is usually a layer of silica or silicon oxy-carbide, optionally modified by additives. The tin oxide layers compared to the layers of the systems deposited by cathodic sputtering, are relatively thick, more than 200nm, and for some more than 450nm. These thick layers are strong enough to withstand exposure to mechanical and / or chemical tests.

An example of a low-e system meeting the desired properties consists of a layer of tin oxide doped with 2 atomic% of fluorine, the thickness of which is 470 nm. This layer is deposited on a layer in contact with the glass, composed of silicon oxy-carbide 75 nm thick. This system on a sheet of clear glass 4mm thick leads to an emissivity of about 0.1.

Other low-e layer systems can be produced by sputtering technique while maintaining sufficient mechanical strength. Systems of this type are, for example, composed of oxides, in particular layers based on titanium oxide in combination with other metal oxides, in particular of zirconium oxide. Layers of this type are described in particular in the application. WO2010 / 031808 .

By way of another example, a system which can be used comprises a layer of an alloy of chromium and zirconium. To protect this metallic layer deposited by cathodic sputtering, it is caught between two layers of silicon nitride. This assembly also leads to a satisfactory emissivity with a reduction in light transmission which can reach 10%, a reduction which for the use in question does not constitute a drawback.

The use of these low-emissive systems considerably improves comfort in the passenger compartment in cold weather and can make the use of a sun awning unnecessary.

Glass roofs according to the invention can advantageously combine several functionalities. Among these, it is advantageous to benefit from the glass roof for lighting, as developed above, but also to have a controlled variation of the light transmission, whether or not this variation is implemented simultaneously.

The use of an SPD functional film is the subject of previous publications and in particular WO2005 / 102688 which specifies some of the conditions of implementation which are recalled below in connection with the figures.

The principle of the application of SPD cells for automobile roofs with controlled light transmission is well known. The use of these films makes it possible to modify very significantly the transmission between two distinct states, a clear state and a dark state. An interest of these systems is, in the dark state, to achieve the almost complete suppression of light transmission. The commercially available films thus make it possible to reduce the transmission in the visible range to less than 1%. This is the state which corresponds to the absence of an electric field. Under these conditions, the glazing provides the desired “private” character in a particularly effective manner. The variation in visible light transmission can be as high as 40% or more between the two states of the film. The choice of films makes it possible, if necessary, to fix the importance of this variation. Users prefer relatively large deviations, and generally these are not less than 30% in the applications envisaged.

If the variation in light transmission is decisive in the choice of SPD films, they have an important role in the energy transmission of the glazing in which they are incorporated. In the dark state, the energy transmission, regardless of the presence of glass sheets or absorbent spacers, is usually less than 5%. The dark state is normally that of the vehicle stationary, a very limited energy transmission is therefore particularly welcome. In the clear state, the energy transmission is appreciably greater due to the very fact that the visible radiation is also accompanied by an energy transmission. The SPD film nevertheless absorbs a significant part of the energy.

The use of SPD films is subject to some requirements apart from those regarding their performance on the modification of light transmission. It is first of all necessary to protect the functional film mechanically and chemically.

The figure 7 illustrates the composition of a roof offering the two functions, lighting and controlled light transmission. As for the roof of the figure 1 we find the two sheets of glass 1 and 2 and the spacers 3, 3 'and 4, and the blade 5 supporting the diodes.

The SPD film is shown schematically at 12. It does not cover all of the glazing. The edges of the SPD film must be protected from contact with the outside atmosphere, in particular to protect the active particles from moisture. To prevent contact with the atmosphere, the SPD 12 film is completely wrapped in the various sheets of interlayer material. To wrap the film 12, an intermediate sheet 13 of thickness close to that of the film is arranged so as to surround it. Appropriate cutting of the sheet 13 makes it possible to surround the film in order to isolate it from the outside. The figure 7 shows the sheet 13 consisting of a single piece in which a recess is provided. It is possible to replace this single part by a set of juxtaposed bands surrounding the film 12 in an equivalent manner. The presence of this sheet 13 isolates the SPD film and simultaneously ensures a uniform distribution of the pressure exerted on the constituents of the glazing during its assembly.

The sheet 13 may or may not be of the same nature as the spacers 3 and 4. The fusion of the different sheets during assembly is facilitated if these sheets are of the same nature.

Another requirement of SPD films is related to their heat sensitivity. In SPD films the particles which are ordinarily incorporated into a polymer matrix can be altered by excessive temperature rise. To a lesser extent, the films can see their properties irreversibly modified if they are exposed to too intense cold, for example - 40 ° C. The exposure to external temperature variations is accentuated by the position envisaged according to the invention. Solar radiation, and in particular infrared rays, can lead to a sharp rise in temperature.

To prevent degradation of the film, provision is made, in particular in the aforementioned text, to have an infrared filter above the SPD film.

It is also desirable to protect the SPD from ultraviolet light. The materials used to constitute the laminates and to encapsulate the cells are usually products which in themselves are UV screens. This is the case in particular with materials such as polyvinyl-butyrals (PVB) or ethylene-vinyl-acetate (EVA) polymers, previously presented for producing the laminated structures of these roofs. The presence of such compounds constitutes a practically complete UV filter. It is therefore not necessary to provide additional elements.

To the figure 7 the functional elements present in the laminate are in relative positions which take account of their possible interdependence. As an indication, the lighting means constituted by the light-emitting diodes are obviously located under the light transmission control film, so that the light flux they produce is independent of the variations in light absorption imposed by this film. .

The light transmission control film, like the lighting means, is necessarily electrically powered. Their connection to the general electric power supply system of the vehicle is necessarily made from the edges of the glazing. The connecting electrical conduits are not normally transparent. In order not to break the transparency, even limited of the glazing, efforts are made to conceal these conduits in the peripheral areas of the glazing, which normally comprise opaque enamelled parts intended in particular to mask the irregular bonding marks. These masks also conceal the limits of the SPD 12 films with their entourage 13. The figure 7 does not represent these enamel bands.

The structure of the SPD type films described in the application WO2005 / 102688 is schematized at figure 7a . This structure comprises a central element 15 made of a polymer containing particles sensitive to the application of the electric field. On either side of this central element 15, and extending on each of its faces, two electrodes 16 make it possible to apply the voltage necessary for the control. In a known manner, the electrodes 16 are advantageously made of essentially transparent sheets coated with thin conductive layers. Most commonly polyethylene glycol terephthalate (PET) sheets a few tens of microns thick which combine good transparency with high mechanical strength. On these sheets, the conductive layers are advantageously of the TCO (thin conductive oxide) type, such as the ITO (indium tin oxide) layers.

As indicated above, the components of SPD films, and in particular particles of an organic nature, are sensitive to aging, in particular under the effect of heat. To give them the desired longevity, the film is normally protected by filters interposed between the outer sheet of glass 1 exposed to solar radiation, and the SPD film 15. Infrared filters are used in many applications in sun protection glazing or in glazing. low-emissivity. They generally consist of thin layers of conductive oxides, or better, because they are much more efficient, of metal layers thin enough to be practically transparent. In these filters, the metal layers are associated with dielectric layers, which are also thin and transparent, which give the assembly the necessary selectivity. Most often to improve this selectivity, which is accompanied by reflection which one endeavors to make as neutral as possible, the filters comprise a plurality of metal layers which are essentially based on silver.

The infrared filtering layers are either applied to the outer glass sheet or introduced through an intermediate polymer sheet, in particular of the PET type. The figure 7b shows a detail of an assembly of this type in which under the outer glass sheet 1, a sheet 14 carrying the infrared filter is placed between two sheets 3 and 20 of interlayer material. Insofar as the support of the PET-type layers is not itself such as to adhere to the glass, it is necessary to introduce it between two thermoplastic interlayer sheets. The use of a support film makes it possible not to subject the fragile layers to high temperatures. The only constraint remains the temperature imposed by passage in the oven during assembly. The counterpart is the fact of having to add an intermediate sheet which increases the thickness of the assembly.

It is also possible to proceed with a system of layers deposited directly on the outer glass sheet. But as indicated, if one chooses very efficient filters, such as those comprising metallic layers, these layers are applied by cathodic sputtering techniques, techniques carried out on flat sheets. Consequently, this solution implies that these layers undergo the heat treatments during the shaping of this glass sheet.

The choice of the layer system is advantageously that of systems with several silver layers in order to obtain an effective filter which allows control of the coloring, in particular in reflection. A particularly effective set of layers is as described in the application WO2011 / 147875 . In this application, the recommended system comprises three silver layers and dielectric layers, the whole being chosen, in particular the thicknesses of the silver layers, so that the coloration in reflection is satisfactory even under low incidence of observation. .

The protection of the SPD film must also take into account the presence of diodes when they are placed in parts of the roof surface covered by this film. The example given above shows, by an appropriate choice diodes and their arrangement, that it is possible to limit the local increase in temperature associated with the operation of the diodes to a few tens of degrees. This increase is in all cases lower than that linked to exposure to solar radiation.

Claims (14)

1. Laminated glazed automotive vehicle roof, comprising means for illuminating the passenger compartment, means comprising a set of light-emitting diodes incorporated between the glass sheets in the interlayer material of the laminate, roof of which the light transmittance TL is at most 50%, the number of diodes and their power being chosen to ensure useful illumination without occasioning prejudicial heating of the constituents of the glazing unit, and wherein the power supply circuit and the diodes are placed on a carrier inserted between the glass sheets of the laminate, said carrier being a glass strip.
2. Roof according to Claim 1, wherein the electrical power of each diode does not exceed 2 W and preferably does not exceed 1 W.
3. Roof according to one of the preceding claims, wherein the chosen diodes have an individual luminous efficacy no lower than 15 lm/W and preferably no lower than 75 lm/W.
4. Roof according to one of the preceding claims, wherein the diodes, used to produce a reading light, lead to a total emission such that the light flux in the passenger compartment, issuing from the glazed roof, is no lower than 1 lm and preferably no lower than 2 lm.
5. Roof according to one of the preceding claims, wherein, to form a reading light, 2 to 20 and preferably 4 to 15 diodes are used.
6. Roof according to one of the preceding claims, wherein a Fresnel lens is placed facing the diodes, in position 4, in order to limit the beam angle of the light flux.
7. Roof according to one of the preceding claims, wherein the diodes are a distance from each other that is no lower than 10 mm and preferably no lower than 20 mm.
8. Roof according to one of the preceding claims, wherein the diodes and the elements located between these diodes and the passenger compartment on the path traced by the light are chosen such that the light flux has an essentially neutral spectrum.
9. Roof according to Claim 8, the spectrum of which is located in the perimeter defined by the points of CIE 1931 coordinates: (0.2600; 0.3450), (0.4000; 0.4000), (0.4500; 0.4000), (0.3150; 0.2900), (0.2350; 0.2500), and preferably in the perimeter defined by the coordinates (0.2650; 0.3350), (0.3200; 0.3200), (0.3100; 0.3000), (0.2350; 0.2500).
10. Roof according to one of the preceding claims, which comprises in position 4 a system of low-E layers, such that its emissivity is at most 0.3 and preferably at most 0.2.
11. Roof according to one of the preceding claims, wherein the power supply circuit of the diodes is formed in a thin conductive TCO layer.
12. Roof according to one of the preceding claims, comprising a control for switching on/off the diodes with a capacitive-type sensor incorporated into the roof.
13. Roof according to Claim 11 and Claim 12, wherein the sensor is formed in the same layer used to form the power supply circuit of the diodes.
14. Roof according to one of Claims 12 or 13, wherein a conductive film connected to ground is interposed between the sensor and the external sheet in order to protect from parasitic influences.

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